Last Halloween we made a fire breathing pumpkin man 🙂
Oh yeah, and it was motion activated. Don’t do this at home.
Original iteration was a last minute cobbling together of a glade air freshener dispenser and an arduino and motion sensor. Next iteration uses a 3D printed holder for a small can of hairspray and a servo, still motion activated. Flame/ignition source I leave up to your risk appetite.
GitHub repo with some simple code and 3D models & assembly suggestions.